What do we mean by climate?

Weather and climate are not quite the same. So what is weather, and what is climate?

Climate, which comes from the Greek klima meaning 'area', usually refers to a region's long-term weather patterns. This is measured in terms of average precipitation (i.e. the amount of annual rainfall, snow etc), maximum and minimum temperatures throughout the seasons, sunshine hours, humidity, the frequency of extreme weather, and so on.

These days, 'climate change' usually refers to global climate change, or long-term variations in the planet's average temperature. But it can also be used more generally to mean local and regional changes in weather patterns. The global average temperature is influenced by many interacting systems which, together, we call the climate system. But, of course, global climate change also affects regional climates.